2 small rads never get hot enough

wicky9 · 22-03-2018 08:20AM #1

Hi all,

I have a pressurised system (I keep it at around 1.5 bar cos that's what last plumber who serviced it said) but there are 2 small rads in my "sun room" (freezing in winter, warm in summer) that never get warm enough. I have bled them and re pressurised the system numerous times but they never seem to get anything other than luke warm. They don't appear to be furthest from the tank but the pipes may travel under the slab and I have a suspicion that it may not be insulated. Would that be a reason why they won't heat? Or am I missing something else? Definite amateur here but the last lad I had out to service the boiler didn't seem to be able to shed any more light

_Brian · 22-03-2018 08:40AM

There could be many reasons, poorly laid out system, poor insulation, sediment in the system.

Has the system been balanced ?? Balancing restricts some radiators to force hot water to others.

wicky9 · 22-03-2018 11:14AM

_Brian wrote:

Has the system been balanced ?? Balancing restricts some radiators to force hot water to others.

_Brian wrote:

There could be many reasons, poorly laid out system, poor insulation, sediment in the system.

I tried blancing it out last year but wasn't overly successful. I might try it again now. Presumably you mean turning various rads up/down by small amounts until you get the desired heat in each rad? Sorry...I'm pretty amateur here as you can guess

Ubbquittious · 22-03-2018 11:32AM

If you close every other rad does it work grand?

wicky9 · 22-03-2018 12:25PM

Ubbquittious wrote:

If you close every other rad does it work grand?

Haven't gone to that extreme.... I'll do that today and report back. If that was to work am I just looking at a pressure problem?

the_pen_turner · 22-03-2018 12:26PM

what do you mean by sun room. is it a conserveratory built like the rest of the house . they are very hard to heat due to all the windows and sticking out on their own.

wicky9 · 22-03-2018 12:31PM

the_pen_turner wrote:

what do you mean by sun room. is it a conserveratory built like the rest of the house . they are very hard to heat due to all the windows and sticking out on their own.

It's built with the house but on the side. It has 4 windows and a patio door in a 25m2 space, so built to trap sun. There are only 2 small rads in it but being so small I reckon if they actually worked they would heat the space fine

Ubbquittious · 22-03-2018 12:54PM

wicky9 wrote: »

Haven't gone to that extreme.... I'll do that today and report back. If that was to work am I just looking at a pressure problem?

In a rare bout of optimism I'm hoping the extra pressure will blow the cobwebs out of the 2 rads and the pipes leading to them and sort it for good. Something similar happened to me not too awful long ago.

wicky9 · 22-03-2018 02:02PM

Ubbquittious wrote:

In a rare bout of optimism I'm hoping the extra pressure will blow the cobwebs out of the 2 rads and the pipes leading to them and sort it for good. Something similar happened to me not too awful long ago.

That has worked a treat!! Thanks. They're absolutely roasting now. Should I turn them all on again now and see do they keep the heat or should I be careful about what I turn on and off??

Water John · 22-03-2018 02:08PM

Open the others a little, as in very small amount. Gradually increase over time.

_Brian · 23-03-2018 08:44PM

There are plenty of procedures online for balancing rads, just google it.

You could start with the hottest fastest to heat rad and restrict that down well, keep working on next hottest.

How about fitting TRV’s to some rads in rooms that heat easily, that way those rads would shut down completely thus driving heat on to the others. You can set some less used rooms lower too.

wicky9 · 23-03-2018 09:24PM

_Brian wrote:

How about fitting TRVâ€™s to some rads in rooms that heat easily, that way those rads would shut down completely thus driving heat on to the others. You can set some less used rooms lower too.

_Brian wrote:

You could start with the hottest fastest to heat rad and restrict that down well, keep working on next hottest.

_Brian wrote:

There are plenty of procedures online for balancing rads, just google it.

Thanks for all that. I think I have it fairly well balanced now, did as you said and started with hottest rads (upstairs).

We have a nest installed upstairs in the baby's room, it keeps his room around 19 which is what's recommended, but as a result downstairs can be a bit neglected. We don't mind cos we have the fire, but now that we've balanced it out a bit better we're getting a far more even heat but truth be told it's probably on a bit longer.

Thanks to everyone for the help. Small rads in the room in question were flaming hot until I started bringing the rads upstairs back into the equation....then they really dropped off, it's obviously that run that takes most of the heat

2 small rads never get hot enough

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